1. Field of the Invention
The present invention relates to a printed circuit board and a magnetic head driving device including the same.
2. Description of the Background Art
Actuators are employed in drives such as hard disk drives. Such an actuator includes an arm arranged rotatably with respect to a rotation shaft and a suspension board used for a magnetic head that is attached to the arm. The suspension board is a printed circuit board for positioning the magnetic head with a desired track of a magnetic disk.
A flexible printed circuit board (hereinafter referred to as printed circuit board) that can be bent is attached to the actuator. The printed circuit board has a base insulating layer with predetermined wiring traces formed thereon, for example (see JP 2009-004053 A, for example). IC (Integrated Circuit) elements such as a preamplifier are mounted on the printed circuit board. Wiring traces of the suspension board are electrically connected to the wiring traces of the printed circuit board. Electrical signals are transmitted between other electronic circuits and the magnetic head through the IC elements on the printed circuit board and through the suspension board.
In general, the IC element such as a preamplifier to be mounted on the printed circuit board has a differential output impedance of about 100Ω. In recent years, recording densities of magnetic disks have been improved and a PMR (Perpendicular Magnetic Recording) system has been introduced, resulting in a growing need for larger currents for writing. This increases power consumption of the IC elements, and therefore development for IC elements with reduced power consumption has been promoted. With the development, lower power consumption for driving the IC elements is required also in the printed circuit board on which the IC elements are to be mounted.